Stress related proteases in Caulobacter crescentus

项目摘要 细菌使用能量依赖性蛋白酶来应对压力条件。这些蛋白酶具有双重功能， 作用：破坏异常的，潜在的有毒的，受损的蛋白质，并产生应激反应信号，通过 调节因子的退化。细胞通常会在应激反应中阻止复制，但蛋白质是如何被调节的呢？ 目前对细菌中导致细胞周期停滞的溶解作用知之甚少。该提案涉及如何 利用生物化学、遗传学和蛋白质组学组合靶向复制因子的应激相关蛋白酶 方法，特别关注来自模型细菌柄杆菌属的蛋白酶和复制因子 crescentus。目的1和2确定在蛋白毒性应激过程中产生的错误折叠蛋白如何直接刺激 延迟Lon蛋白酶以破坏复制起始物DnaA并在胁迫期间引起生长停滞。目标3 和4集中于ClpXP蛋白酶对钳装载子亚基DnaX的部分加工如何对于 DNA损伤过程中的复制应激耐受。因为这些蛋白酶和复制因子是高度 这些结果将影响我们对复制，蛋白质组学， 姐妹和压力耐受性。这些蛋白酶在细菌毒力和致病性中的关键作用， 与细菌应激反应中对这些蛋白酶的普遍需求，表明它们优于 为开发人类健康急需的新抗生素战略提供了目标。

Project Summary Bacteria use energy dependent proteases to respond to stressful conditions. These proteases serve a dual role: destroying aberrant, potentially toxic, damaged proteins and generating stress responsive signals through degradation of regulatory factors. Cells often arrest replication in response to stress, but how regulated prote- olysis contributes to cell cycle arrest in bacteria is currently poorly understood. This proposal addresses how stress related proteases target replication factors using a combination of biochemical, genetic and proteomic approaches, specifically focusing on proteases and replication factors from the model bacteria Caulobacter crescentus. Aims 1 and 2 determine how misfolded proteins generated during proteotoxic stress directly stimu- late the Lon protease to destroy the replication initiator DnaA and cause growth arrest during stress. Aims 3 and 4 focus on how partial processing of the clamp loader subunit DnaX by the ClpXP protease is critical for replication stress tolerance during DNA damage. Because these proteases and replication factors are highly conserved throughout all bacteria, these results will impact our general understanding of replication, proteoly- sis, and stress tolerance. The critical role of these proteases in bacterial virulence and pathogenicity, together with the universal requirement for these proteases in bacterial stress responses, suggests that they are excel- lent targets for development of new antibiotic strategies that are of immediate human health need.